After the upgrade from 29.0.4 to 29.0.5 RC1 I see in the NC Admin Overview
“One or more mimetype migrations are available. Occasionally new mimetypes are added to better handle certain file types. Migrating the mimetypes take a long time on larger instances so this is not done automatically during upgrades. Use the command occ maintenance:repair --include-expensive to perform the migrations.”
After run :
sudo -u www-data php occ maintenance:repair --include-expensive
The problem has not been resolved and the message still appears.